[Biophsical study of dental tissues under the effect of a local strontium application].

Microradiographic and electronmicroscopic observations show that topical application of concentrated strontium chloride solution on an abraded dentinal surface caused the formation in the dentine of very compact superficial layer composed of fine granules and with a high degree of radiodensity. This layer not only forms a continuous deposit on the superficial zone, but also penetrates and fills the canclicules to a certain distance. A barrier is thus created, diminishing the permeability of the dentine, which would explain the desensitization of the tooth. Electron probe microanalysis and X-ray diffraction studies show that the fundamental mechanism of the formation of strontium deposits is an exchange with the calcium fo the dentinal tissue, and recrystallization in the form of strontium apatite.